JPH02117025A - Isolator for contact blade - Google Patents

Abstract

PURPOSE: To provide an integral composite for isolating and insulating all contact blades of one phase of a circuit breaker by an insulating device by providing a means for keeping the space between contact blades and a means for shielding the lower surfaces of the contact blades from arc on the insulating device. CONSTITUTION: This device has 10 contact blades 18 isolated by a movable contact blade barrier 20, the barrier 20 is formed of a component having a plurality of spacers 22 for keeping the space between the contact blades 18, an engaging part housing hole 24, and a bulkhead 26, and the engaging part housing hole 24 gives the space for mounting a device for rotating the blades 18 on the barrier 20. The device for rotating the blades 18 is mounted on the barrier 20, whereby the blades 18 are uniformly rotated to simultaneously open contacts 10, 12. Further, the spacers 22 and the engaging part housing hole 24 cooperate with a partitioning wall 28 so as to form an air gap 30 between the blades 18, an the air gap 30 helps electrically and thermally insulate the blades 18 each other.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a main contact blade assembly of a switchgear, and more particularly to a device for spacing and isolating a plurality of circuit breaker contact blades.

BACKGROUND OF THE INVENTION When current-carrying contacts of a circuit breaker are opened while current continues to flow through the contacts, an arc typically forms between the contacts. Depending on the strength and duration of the arc, the contact material and the material surrounding the arc may experience varying degrees of degradation. In addition, the contact surface may be eroded. In dealing with this problem, it is desirable to extinguish the arc as quickly as possible, or to move the arc from between the contacts to a location where damage from the arc will not adversely affect the operation of the circuit interrupter.

In addition, it is important to keep the contact support blades of the circuit breaker isolated and regularly spaced, while also insulating the individual contact blades. One way to insulate the individual contact blades is to insulate each blade with an insulating material. It is to cover it with.

During disconnection of electrical equipment under fault conditions, various electromagnetic forces act on the components of the circuit breaker, in particular the parallel current-carrying paths in the contact blades tend to generate electromagnetic forces that pull the contact blades together. be. One way to protect the contact grades from being drawn together is to insert individual spacers between the contact blades.

It is therefore important to provide a means of isolating the contact blades. Additionally, it is important to provide a means to extinguish the arc or move the arc to a location where damage from the arc is not a danger.

OBJECT OF THE INVENTION It is an object of the invention to provide means for maintaining isolation of a plurality of contact blades of a circuit breaker device. Another object of the invention is to provide means for displacing and extinguishing arcs at the main contacts of a circuit breaker.

[Means for Solving the Problem] This problem is based on the present invention, and an insulating device that maintains a spacing between a plurality of contact blades includes a means for maintaining a spacing between the contact blades and a means for shielding a lower surface of the contact blade from an arc. This can be solved by being prepared.

ADVANTAGEOUS EFFECTS OF THE INVENTION An advantage of the present invention is that the isolation device provides an integral assembly for isolating and insulating all contact blades of one phase of a circuit breaker. Using a one-piece assembly for this purpose reduces assembly costs by eliminating the need to insert individual spacers between the contact blades. Another advantage of the invention is that the isolation device provides an isolation means to prevent arc movement along the underside of the contact blade. Yet another advantage of the invention is that the isolation device can help uniformly lift the contact blade. Yet another advantage of the invention is that the heat of the arc can vaporize a portion of the insulating device so as to generate gas in close proximity to the arc to displace and extinguish the arc.

[Embodiment] Next, the present invention will be described in detail with reference to drawings showing an embodiment of a contact blade barrier based on the present invention.

FIG. 1 shows the current carrying path for a molded circuit breaker.

Opening and closing of the current carrying path is accomplished by opening and engaging contacts 10.12. In order to carry a predetermined current, a plurality of contacts 10 are typically used, each carrying a portion of the total load current. In order to provide a current carrying path allowing opening and closing of the contacts 10.12, the current carrying path from the terminal 14 comprises a pivoting contact 16 which cooperates with a movable contact blade 18. For each contact 10 there is a respective associated blade 18.

FIG. 2 shows ten contact blades 18 separated by moving contact blade barriers 20. FIG. The helier 20 is a molded element that includes a plurality of spacers 22 that maintain the spacing between the contact blades 18, an engaging portion receiving hole 24, and a separating wall 26.

Engagement receiving hole 24 also provides a location for attaching a device to barrier 20 for rotating blade 18 . By attaching to the barrier 20 a device for rotating the blades 18, the blades 18 are rotated uniformly, thus opening the contacts 10.12 at the same time.

In addition to providing a means for isolating the blades 18, the spacer 22 and engagement receiving bore 24 cooperate with the partition wall 28 to form an air gap 30 between the blades 18. Air gap 30 helps isolate blades 18 from each other electrically and thermally. Air gap 30 also provides a means for circulating air along the sides of blade 18 so that blade 18 can be cooled.

FIG. 4 is a cross-sectional view of the barrier 20 taken along the cut line of FIG.
, so the blade can rotate uniformly. In addition, insulating portion 32 insulates lower edge 36 of blade 1B so that arcs occurring between contacts 10 and 12 are prevented from propagating along lower edge 36 of blade 18. Steam generating portion 34 also prevents arc propagation along the lower edge of blade 18. In addition, steam generating section 34 provides arc extinguishing steam in the vicinity of the arc when section 34 is heated by the arc.

Barrier 20 can be made of, for example, a high temperature, highly insulative arc-quenching material. This type of material is suitable for providing the necessary strength for the barrier 20 and also provides an arc-extinguishing dropout when the material is heated by an arc.

Although one embodiment of a contact blade barrier has been shown and described in detail, various other changes and modifications may be made without departing from the scope of the invention.For example, the barrier may be adapted to cooperate with a varying number of contact blades. can be adapted to do so. Additionally, depending on the type of device used to rotate the blade, the engaging portion receiving hole can be made to have a variety of shapes. For example, the insulating portion 32
By passing an air gap 30 through the air gap, the air gap can be formed such that cooling is optimized for a given blade shape.

[Brief explanation of drawings]

1 and 2 are a side view and a plan view, respectively, of a contact device of a switchgear incorporating an embodiment of a contact blade barrier according to the present invention, and FIGS. 3 and 4 are respectively shown in FIG. 1. 4 is a plan view of the contact blade barrier and a sectional view taken along the section line of FIG. 3; FIG. 18...Contact blade 20...Contact blade barrier 22...Spacer 24...Engaging part accommodation hole 26...Separation wall 28...Partition wall 30...Air gap 32... Insulating part (first part) 34... Steam generating part (second member) FIG. FIG.

Claims (1)

Claims: 1) a plurality of contact blades each defining a lower surface, the isolating device comprising means for spacing the contact blades and means for shielding the lower surface of the contact blades from arcing; Isolation device for contact blades that maintains the distance between the contact blades. 2) A device according to claim 1, characterized in that the means for spacing the contact blades comprises a plurality of spacers. 3) The device of claim 2, wherein the means for spacing the contact blades further comprises a plurality of partition walls. 4) Device according to claim 3, characterized in that the means for maintaining the spacing of the contact blades comprises at least one engagement receiving hole. 5) The apparatus according to claim 4, further comprising means for generating arc-extinguishing steam when heated by an arc. 6) A plurality of circuit breaker contact blades, each of the contact blades defining a lower surface and a contact means, comprising means for spacing the contact blades and a member for shielding the lower surface of the contact blades from arcing. Barrier for contact blades to maintain and support spacing. 7) A first part whose shielding member shields the lower surface of the contact blade, and a second part which shields a portion of each contact blade and generates arc-extinguishing steam in the vicinity of the contact means when heated by the arc. 7. A barrier according to claim 6, characterized in that it comprises: 8) The means for spacing the contact blades comprises at least two spacers, the spacers and the two blades cooperating to form at least one air gap adjacent the blades. barrier.